Of Gaia and Grimm
by DestroyerZ0
Summary: After Eggman attempts to reawaken Dark Gaia, Sonic and the fragments of the dark beast are sent to a mysterious new world.  With Chip by his side, they must find a way to defeat Dark Gaia once again. Remnant is about to experience a new age of darkness.
1. Prologue

"_For as long as humanity can recall walking the surface of Remnant, so do they remember this wicked force." _

_World of Remnant: Episode 3_

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"_The abomination grows strong on the negative energies of the world, sleeping within its core for millennia in wait…"_

_Gaia Manuscripts, 4:11_

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**It's been a while huh?**

**I've had this idea in my head for a while now, and I've decided to finally make use of that. I'm honestly surprised no has done this crossover yet. The idea of two similar, yet very different creatures meeting each other interested me. And now here it is. The Dark Gaia Spawn and the Creatures of Grimm. Creatures of darkness colliding. How will the world of Remnant react when they learn of the existence of another dark force? How will Ozpin and Salem react? Time will tell.**

**Tell me what you think about the concept. I'm interested to hear what people think of it.**


	2. Only the beginning

High above the Earth's atmosphere, an enormous fleet was orbiting the blue planet, each with enough firepower to demolish a small city were slowly treading along their path. Ginormous cannons and rockets were mounted on the death machines in a show of power. This was the Egg Fleet, the grand armada of the Eggman Empire. To the world, it was a sign of power and instilled fear into the hearts of the people. Unfortunately for Dr. Eggman, the pain in his mustache was once again here to foil his evil schemes. This "pain in his mustache" held many names: the Blue Blur, the Fastest Thing Alive, the Freedom Fighter, the list went on. But most commonly, he was known as Sonic The Hedgehog.

Gunshots and explosions rang out as they all missed their target. Robots flew across the ship's deck chasing the blue streak. Sonic tore the Egg Fighters like they were paper as they tried to fight back. Fortunately for the spiny blue hedgehog, being faster than sound makes you hard to hit. Catching up to him, Aero-Chasers took aim and fired laser beams at him. Sonic quick steps left and right to avoid the incoming barrage. The machines whir in agitation, that hedgehog was always so unbelievably fast!. From the deck of the ship, massive cannons rose up and pointed towards the blue hero as he continued running. Their energy shots left a yellow streak behind them as they rapidly closed in on their intended target. Sonic anticipated the shot and swiftly adjusted his position so that the projectiles hit the group of Aero-Chasers in a fiery explosion.

Sonic smirked as he sped past the metal debris behind him. "Hah! Too easy!", he mocked. Did Egghead honestly think he could hit him? Well, he'll just have step it up!

And step up his game the Doctor did. He glanced behind and saw a pair of Interceptors closing in on him. The machine on the right fired a beam from its center. Sonic dodged to the left only to quickly move right again as the robots twin shot another beam from its right shoulder. The first bot slammed its fist into the ground and produced a small energy wave. The blue hero hopped over it as at passed. The other robot swung with its left arm as Sonic slid under. He took this moment to counter attack as he jumped and shot towards with his signature Homing Attack. He impacted the Interceptor with enough force to knock it into a pillar as it burst into flames. Not a moment after its destruction, Sonic was running down a corridor with the remaining machine in pursuit.

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Somewhere in a dark room, the nefarious Dr. Eggman watched as his nemesis raced down the corridor, the camera solely focused on him.

He smirked.

"Hehehe… I've got right where I want you! You've caused enough today you nasty little pincushion! Your jog ends here!"

The Doctor rose from his seat and turned to see two small robots playing with a deck of cards. The one on the right, who seemed to be winning, had a round body with a red and black color scheme and two bright, glowing aqua colored eyes was known as Orbot. The one on the left had a more cubical body, sporting a yellow and black color scheme. From looks alone, one could tell he wasn't very bright. This one was known as Cubot.

"Hmm… do you have any fours?", Cubot asked his companion.

"Go fish.", Orbot responded.

"Aww, dang it!", the yellow bot whined. "How are you so good at this game!? It's not even fair anymore!"

The red machine shrugged in return. "I'm honestly not that good, you're just so unbelievably terrible that I always win."

Cubot glared at him and grumbled in annoyance.

"Quiet you bolt brains!", Eggman yelled. "Orbot! Prepare the machine for activation! Cubot! Close the appropriate blast doors to lure the hedgehog where we want him!"

Cubot raised his arm and saluted. "On it boss!" He put down his cards and floated over to the main console. He pressed a few button and looked up to the screen to see multiple doors sealing shut. "We've got you now Sonic! The Doctor said so, after all!", he responded happily.

Orbot, however, was more hesitant. "Sir, are you certain that's such a good idea? Even with all seven Chaos Emeralds in our possession, there's no guarantee that your plan will succeed. It could, quite literally, blow up in our faces." He had every reason to be concerned. The Doctor's last attempt to harness Dark Gaia's limitless power had almost resulted in worldwide destruction. There was no telling what would happen if he were to awaken it prematurely a second time would do.

Sadly for him, the mustached man was not worried in the slightest. "What? My brilliant plan not succeeding? Impossible! I've been working on this for a very long time now. I worked out the details and determined the perfect strategy to finally best that blue menace!" He roared his head back and laughed maniacally. His plan was foolproof!

The red robot sighed. _Why did I expect anything less?_ Eggman was going to release Dark Gaia, no matter how bad of an idea it might be.

Eggman stopped laughing. "Enough talk! It's time to put everything into motion. Cue the music!"

_Click_

"_I am the Eggman! That's what I am! I am the Eggman! I've got the master plan!"_

He spun around to find Cubot next to the speaker systems. He was playing his "theme song" that was created for him by the Eggman Fan Club. Unsurprisingly, all its members were robots. They thought that giving him his own theme would make him seem more imposing. All it did was make him look like some video game villain. He wouldn't be surprised if he heard that song play anytime he entered a room. Strangely enough, he felt this weird feeling inside him. Almost like someone told him a joke and missed it completely.

Huh.

Eggman growled. "I didn't mean literally you bolt brain! Shut off the speakers and get back to work! We can't waste anymore time!"

"_-obstacle that always gets in-"_

_Click_

The music shot off and Cubut went back to the panel he was at before. Orbot turned around and made his way through a small door. Inside that room was a small teleporter that was meant to transport him directly to the Chaos Energy Cannon.

With both robots resuming their work, the nefarious doctor turned back to the main screen where Sonic was still running down the narrow halls.

He glared at the screen. "You can run as fast as you want to hedgehog, but you're too late. I've already won."

He smirked.

Sonic had no idea what was to come.

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"_Closing blast doors"_

As Sonic sped through the corridors of Eggman's dreadnought ship, he heard multiple doors seal up, preventing access to certain areas. Then, the door ahead of him closed, forcing to go left as the Interceptor was still chasing him. From the walls, dozens of turrets fired upon him as he moved to dodge a laser from behind him. Looking ahead, he saw that the floor had been electrified.

Sonic simply chuckled. "Heh. Nice try Egghead, but you'll have to do better than that!" Just as he reached the electric floor, he jumped onto the wall and slightly increased his speed he ran along it. Behind him, he saw the Interceptor now accompanied by a pair of Aero-Chasers. The smaller robots fired multiple small rockets at him. He avoided them with ease as the wall turrets kept the pressure on the blue hero. The larger robot swung its right fist at him, but instead of hitting Sonic, its fist was now stuck in wall.

Sonic laughed out loud. "Sorry buddy! You're just _too slow!_" He then saw a pole sticking out the wall he was running on. He reached an arm out to grab it and spun himself around towards the Interceptor. He jumped into a ball before smashing into the large machine, cracking its middle eye. As he fell, he used both arms to grab hold of its arm and flipped onto it. Using the momentum, he flung himself back at the same wall and continued to speed along it. The Interceptor fell limp shortly after.

Now seeing the floor return to normal, he jumped off the wall and returned to the ground as the Aero-Chasers now fired their machine guns. _'Looks like Eggman's machines got upgraded'_, Sonic thought to himself. The two bots moved to his front side, maintaining a set distance. They fired incendiary missiles at the ground, creating fire traps for the blue blur. He stepped to the right, avoiding the first fire pit. He dashed left, avoiding the next two fire traps. His movements were rapid, precise. Even at such great speeds, he was able to keep a steady pace. Nearing the electrical trap, he hopped over it before jumping up higher and homed in on one of the machines, tearing it to pieces. Its twin noticed him still in the air and shot at the hedgehog. Narrowly avoiding the bullets, Sonic used his stomp technique to swiftly reach the ground. He spun his body in a ball and launched himself at the green machine, knocking it into the wall before exploding. Heh. Just more for the scrapyard!

He landed on the floor and gave himself a quick spin on his shoes before dashing away.

As he ran, he glanced behind him and saw that the blast doors closing in quick succession. Seeing this, he increased his speed to escape the corridor. Even with his increased velocity, the gateways were shutting just as fast. As he reached the of the hallway, he saw the final blast door seal shut. Being unable to turn around, he decided to use the only technique that could get him through metal that thick. Sonic's body became engulfed in a powerful blue aura as his speed increased immensely. He shot forward like a missile as he obliterated any robot in his path. The air around him shook as he practically flew like a bullet. Nearing the metal door, he sped up ever so slightly as he pierced through it light it was paper.

As he slowed to a halt, he saw that the room had a lot of windows viewing the planet. The only thing that was worth noting was the large monitor in front of him.

"Huh. Looks like a dead end. Oh well, time to find a different route", Sonic thought out loud to himself. However, as turned around to leave, the exit was blocked by an energy field.

"Wha!?"

The monitor behind Sonic sparked to life and heard laughter coming from. That laugh… he'd recognized it anywhere. It was…

"Hey! Baldy McNosehair!", Sonic mocked.

The machine was now working completely, revealing McNosehair himself.

Eggman growled. "I go through all this trouble to set a dramatic reveal and this is the thanks I get? You ungrateful little rodent!" Seriously! He spent all this time and effort to make his entrance worthy of a trophy and _this_ is what it amounts to?

The blue hero chuckled. "Sorry Eggface! You just make too easy sometimes. So, what's your evil plan _this_ time? Are you gonna steal all the ice cream in the world and create a monopoly?", he said with a smug smile.

The Doctor snarled. "Laugh all you want hedgehog. My current plan to rule the world us much more ambitious than taking away your dessert. You can't stop me this time! I've already won!"

As he said this, Sonic heard the speaker systems come to life as he heard a voice.

"_Alert! Excessive Chaos Energy detected! Alert! Excessive Chaos Energy detected!"_

"H-huh?", Sonic stuttered. "Eggman! What do you think you're doing!?"

The mad scientist chuckled darkly. "Like I told you, you're too late to spot me. It's already begun."

The blue hedgehog looked out to space and saw what he feared.

The Chaos Energy Cannon.

He watched as the machine powered up, while he was trapped in this room. He heard the voice on the speakers again.

"_Chaos Energy Cannon at full power. Firing main cannon"_

From the opening of the machine, an enormous beam of energy shot towards the Earth, impacting the ocean. Sonic could only watch as the planet was struck.

However, something was different this time. Instead of a purple beam, this one was bright white. What was even more confusing was the fact that the planet did not break apart. The final thing that had him confused was the cloud of dark energy leaving the planet and being sucked up by the white beam.

He turned back to the screen to see Eggman laughing his mustache off. What in the world was going on!?

Eggman spoke up. "Surprised? You should be! Perhaps it would be better if I explained my brilliant scheme. You see, after my failure with Dark Gaia, I realized something. While harnessing Dark Gaia's limitless energy was relatively simple, the problems arose when you and your little sidekick started putting the planet's pieces back together. As each Gaia temple was restored, Dark Gaia's power lessened due to the Chaos Emeralds regaining their full power. Then I thought of something. What if I could release Dark Gaia and eliminate anything that would weaken the creature? After months of theorizing, I discovered the perfect solution! However, the Chaos Emeralds alone wouldn't be powerful enough to help me continue my master plan. Then I had the genius idea of using Dark Gaia's own power to strengthen the Emeralds. Now with their increased power, I can finally complete what I set out to accomplish!", Eggman finished as he fell into maniacal laughter.

Sonic reeled back in shock. "What!? Are you insane Eggman! You have no idea what that much power could do!" He knew Eggman can sometimes get a little ahead of himself, but this time takes the chili dog.

The mad doctor only laughed some more. "Of course I'm insane! Insanely genius!" After a few second he stopped laughing and gained an evil smirk.

Eggman spoke up again. "Well, since you're trapped in this room, I might as well tell you my masterful plan. For dramatic build up, of course. You see, humanity's own negativity is the largest source of negative energy in the world, and because of this, I would need to find a place with just as much negativity and have the Gaia Temples absent. At first, I thought it would be impossible. However, with the combined powers of Dark Gaia and the Chaos Emeralds, I found the perfect location to suit my needs." As he explained, another screen lit up to show the Earth from orbit.

At least, that's what Sonic first thought.

Upon closer inspection, he saw that the planet was not Earth, but an entirely different one with similar features. Most of the planet was dark, with no lights visible in sight, and only one side of the mysterious world had any signs of civilization. It was… bizarre.

Sonic looked back with a confused expression. "What are you getting at? What is this place? What are you up to Egghead?", he asked. Something just didn't feel right here. What was with this planet? Where the city lights? Most of the world should be covered in them. Just what was this place?

"You're probably thinking, 'just what is this place?'. Well, allow me to answer your question. This planet is very similar to our own, yet so different at the same time. It's no coincidence that they share many familiar traits. This planet is in a parallel dimension!"

Sonic raised an eyebrow. "Parallel dimension? I thought you learned your lesson about messing with time and space after the whole Time-Eater thing. What makes think this will end any differently? We both know you'll just end up right back where you started, wondering how you could've lost!" Sonic smirked. It's only a matter of time before he kicks Eggman's mustache into next week. Unless he's busy next week. He wouldn't want to be rude.

Eggman growled. "That's what you think you miserable little rodent! I'll show what happens to those that dare oppose the Eggman Empire!" He pushed a button on his console. "Orbot! Begin the process! Activate the machine! It's time I finally show this pincushion his place!"

Sonic laughed. "Hah! We'll see about that!" He turned to the energy field and began charging up his famous spin dash. He let himself fly at it…

...only for him to be repelled back and hit the floor with a thud.

"Oof!", Sonic grunted. Ow… that kinda hurt. What is this shield made of?

Eggman howled with laughter. "Don't ever bother! That force field is generated from Chaos Energy! You can't escape!" He laughed even harder.

Sonic stood up and charged again. He was immediately pushed back.

Eggman ceased laughing with a victorious smile on his face. "Computer! Analysis!", he ordered.

The speaker activated.

"_Dark Gaia energy completely absorbed. Energy exceeding maximum capacity. Chaos Energy Cannon fully powered. Warning! Warning! Excessive energy readings!"_

Eggman smiled. "Computer! Codename: Gaia!", he said.

The machine responded. _"Acknowledged. Releasing excessive power. Activating…"_

Sonic looked out the window to see Eggman's enormous machine engulfed in a white light. He spun to see Eggman laughing maniacally. "Eggman! What the heck!? This is going too far! Even for you!", he yelled.

The Doctor's laughter died down slightly. "Too far, eh? This is only the beginning! It's over hedgehog! I win!", he responded and he resumed laughing in victory.

The light was quickly reaching Sonic as he shielded his eyes with arms as the world went dark.

But not before hearing a faint voice. It was almost impossible to hear, but his enhanced hearing was able to catch it as everything went silent.

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"_Chaos Control"_

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**Chapter 2 preview:**

"_...strange object in the sky…"_

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"_...scientists are calling the discovery of a lifetime…"_

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"_...it struck the ocean…"_

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"_...creatures seen at night…"_

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"_...there's too many! Fall back!..."_

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"_...Headmaster? What do we do?..."_

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"_..."_

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**Wow. So there we have it folks. The first chapter of this story. Bet you weren't expecting that to happen. Bet you weren't expecting such a cliffhanger as well.**

**I know this took a while, but with school and testing I haven't had very much free time. But that's not important right now.**

**I really hope you enjoyed the first chapter to this grand adventure. I put so much time and effort into this so it doesn't end up like some bad Sonic OC story or something like that. **

**Unfortunately, I can't promise when the next chapter will be released, so I hope you'll forgive me for that.**

**So with that, tell me what you thought of this and tell me if you caught some of the references and jokes.**

**I'll see you all later!**

**Also, Pingas.**


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